What thermostats do you all use to run your HVAC on the C-8 hub? Currently, I have a single stage air conditioner, but I plan to upgrade to a heat pump when it dies. What works well that can be controlled locally.
My heats runs off a boiler with seperate thermostats.
I plan on using a ton of automation, I just want to be able to adjust the temperature from the dashboard when I'm not home.
Single-stage? There are lots of zigbee and zwave options.
Two-stage - your options are more limited; my experience has been that ecobee units have worked well. So has the GoControl zwave unit. The Honeywell T6 pro was terrible.
Fully variable speed? Unless you go with very specific manufacturers - like Bosch or Daikin, you’re restricted to proprietary communicating thermostats.
I'm curious what you think is terrible about the T6. For me the Zwave is rock solid, but the actual control algorithms used just couldn't regulate temps as tight as I would like, no matter how many "cycles per hour" I used in settings to correct it.
I've seen other people say they are great for regulating temps, so it may really depend on your house or the specific zones being controlled. I actually graphed them compared to a Zigbee temp sensor, and there is as much as a 5 degree swing in temp control, even though the thermostat will tell you it is right on target. The screen lies, and most of the time it just reads what it is set to, unless temps are really off from target by a few degrees.
They are terrible if you have multi-stage equipment. I've heard this from several people here and from friends/family that tried them.
That being said, I don't have multi-stage equipment but I tried the T6 for a while. I had 2 of them, one per floor/zone. They were terrible in my home for the same reason you mention about being able to regulate temps. The CPH method used by Honeywell thermostats just does not work for me. In Winter, my heat/boiler was turning on way too often so that the house often got too hot. During AC season, my outdoor compressors were cycling on and off so often it was if they never shut off. Not good for the equipment or regulating temperatures. I played with the CPH settings numerous times. Nothing worked to my liking. This, of course, is just my opinion based on how the T6 worked in my home.
To answer @mjh.iot's question, I now use Ecobee Premium thermostats. I have them integrated to Hubitat via Homekit Controller for local control (although they are pretty much set and forget for me).
@chrisbvt - this exactly! I’ve documented how poorly Honeywell’s CPH method works with a 2-stage HP a few years ago here. You can search the forum for posts from 3-4 years ago.
Honeywell does make other thermostats that work well with multistage equipment. But not their consumer grade T-series.
There are other zwave thermostats that handle multistage better - GoControls for example.
I run one on my two stage HVAC. It was cycling more often than I liked but solved that by adjusting internal settings from 3 cycles per hour to just one. The HVAC stages work correctly with it. Been running mine since middle spring and it has been solid. There was a bit of a learning curve mostly in understanding how Hubitat's scheduler and modes worked with it. Don't use the Thermostat Controller app with it. Just use the scheduler. The T6 Pro is z-wave and reports nothing back to Honeywell. The 2007 version has the newer z-wave radio. I still have my 3rd Generation Nest in a box and have not re-installed it.
Yeah, I played with that setting for a while and I tried all the cycles per hour options, it just didn't help. The temp swing was very noticeable, I could tell when the heat was going to come on because it felt cold in the room, and when the heat has been on because it started to feel too hot. Several degrees of swing no matter what I changed cycles per hour to, and feeling too cold or too hot all day.
I gave up on the T6s controlling things, and I wrote my own anticipating virtual thermostat driver, and I wrote a controller to go with it to operate the zone valves based on the operating state of the virtual thermostats, and it syncs all settings to the T6s. It has been working great once I got it dialed in!
My driver anticipates the need for heat before it gets below target, as it takes time for the heat to come up. It then runs timed cycles, with the heat cycle times based on outside temp and a zone coefficient, and then it does a wait cycle between heat cycles to see if the temp is rising yet, and if temps start rising during the wait, and it is near setpoint, it stops heating to avoid going over target, else it runs another timed cycle. Since baseboard heat continues to heat after the furnace is off, it ends up just a tad above the setpoint (like a few tenths of a degree) by turning off before reaching target. By starting the cycles before going below target, I end up only a few tenths of a degree below target before the heat heat comes up and it starts rising again. There is also a setting for ramping temp, so when temps are enough below target, it ramps continuously until it gets just under target at the ramp setpoint, with temps ending up just barely over target after the ramp.
The controller apps sync the virtual thermostats to the the T6s (I have three zones). It makes the temp on the thermostat read correctly, by comparing the thermo temp to the Zigbee temp sensor that runs the virtual thermostats. I then make the thermostat read the same as the Zigbee sensor by using the temp calibrate command in the T6 driver to change what it displays, to make it match Zigbee temp. Also, any changes on the T6s for mode or setpoint are synced over the the virtual thermostats, so the T6s are now just dumb display and control panel devices, and they are not connected to anything physically other than power.
It also works well in cool mode, where the virtual thermostats control window ACs and a mini-split, with the AC units controlled by the controller app based on operating state of the virtual thermostats.
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